1. Field of the Invention
The present invention relates to needle curving devices. More particularly, the invention relates to a rotating needle curving device for sequentially curving a multiplicity of needles.
2. Description of the Related Art
The production of needles involves many processes and different types of machinery in order to prepare quality needles from raw stock. These varying processes and machinery become more specialized in the preparation of surgical needles where the environment of intended use is in humans or animals. Some of the processes involved in the production of surgical grade needles include, inter alia: straightening spooled wire stock, cutting needle blanks from raw stock, tapering or grinding points on one end of the blank, providing a bore for receiving suture thread at the other end of the blank, flat pressing a portion of the needle barrel to facilitate easier grasping by surgical instrumentation, and curving the needle where curved needles are desired. Conventional needle processing is, in large part, a labor intensive operation requiring highly skilled workmen. Generally, extreme care must be taken to ensure that only the intended working of the needle is performed and the other parts of the needle remain undisturbed.
Curved needles have advantages over other needle configurations in many surgical procedures for a variety of reasons including, uniformity of entry depth for multiple sutures and proper "bite" of tissue surrounding the incision or wound. When providing curved needles for surgical procedures it is desirable for the needles to have a specified curvature, i.e., a predetermined radius of curvature. The predetermined radius of curvature for the needle varies with specific applications and the size of the needle.
Conventional needle curving techniques create the curve by manually forming the machined needle around an anvil structure having a desired curvature. To attain the desired needle configuration, the anvil structure provides a shaping surface for forming the needle. Typically, the needle in positioned for curving by manually holding the needle in engagement with the anvil structure with a holding device. The needle is subsequently bent by manually manipulating the holding device so the needle curvature is formed about the shaping surface of the anvil structure.
When needles are made of steel or similar resilient materials, the anvil or mandrel used may have a smaller radius than the radius desired in the final needle. This configuration allows for some springback after the bending operation and ensures that the desired radius of curvature is attained. A disclosure of such features may be found in, for example, U.S. Pat. No. 4,534,771 to McGregor et al.
One disadvantage to conventional needle curving techniques is that only one needle can be curved around an anvil structure at a time. Another disadvantage is that the needle is manually positioned for engagement about the anvil surface. Lastly, the incidence of needle damage during the curving process is relatively high due to the manual placement and bending of the needle.
One way to overcome the above drawbacks is described in commonly assigned U.S. patent application Ser. No. 07/958,926 to Bogart, filed Oct. 9, 1992. Bogart is primarily directed to automatically curving a multiplicity of needle blanks simultaneously via reciprocating rollers. The present invention provides an alternate way to address the above mentioned drawbacks by providing a system which sequentially presents needle blanks for curving via rotating at least one roller about a mandrel.